This invention relates to a light-sensitive silver halide photographic material with improved color reproducibility and increased resistance to color change or fading of a dye image due to light, heat or humidity.
As the method for forming a dye image using a light-sensitive color photographic material, there may be mentioned the method in which a dye is formed through the reaction between a coupler for photography and the oxidized product of a color developing agent. For the coupler for photography for effecting ordinary color reproduction, the respective couplers of magenta, yellow and cyan, while for the color developing agent, an aromatic primary amine type color developing agent, have been recommended. Through the reaction of the respective couplers of magenta and yellow with the oxidized product of an aromatic primary amine type color developing agent, dyes such as azomethyne dye, etc. are formed, and through the reaction of a cyan coupler with the oxidized product of an aromatic primary amine type color developing agent, dyes such as indoaniline dye, etc. are formed.
Among them, for formation of a magenta color image, 5-pyrazolone, cyanoacetophenone, indazolone, pyrazolobenzimidazole, pyrazolotriazole type couplers, etc. may be used.
In the prior art, most of the magenta color image forming couplers practically used have been 5-pyrazolone type couplers. The color image formed from a 5-pyrazolone type coupler is excellent in fastness to light and heat but is not satisfactory in the tone of the dye. This is due to an unnecessary absorption in the yellow component existing at around 430 nm and also the absorption spectrum of visible light at around 550 nm being broad, whereby color turbidity may cause the photographic image to lack clearness.
As the coupler having no such unnecessary absorption, 1H-pyrazolo[3,2-c]-s-triazole type coupler, 1H-imidazo[1,2-b]-pyrazole type coupler, 1H-pyrazolo[1,5-b]-pyrazole type coupler or 1H-prazolo[1,5-d]tetrazole type coupler as disclosed in U.S. Pat. No. 3,725,067; Japanese Provisional Patent Publications No. 162548/1984 and No. 171956/1984 is particularly excellent.
However, the dye color images formed from these couplers have very low fastness to light. When these couplers are used for light-sensitive materials, particularly those suitable for direct viewing, images will be impaired by usual conditions of storage and use.
Thus, they have disadvantages in practical application. Accordingly, as a method for improving light resistance, it has been proposed to use a phenol type or phenylether type antioxidant, as disclosed in Japanese Provisional Patent Publication No. 125732/1984. However, no satisfactory effect improving light resistance could be obtained.
On the other hand, there exist a coupler having good light-resistance according to the structure of the above magenta couplers. However, they have little fastness of color image to heat or humidity and as a result, they have a disadvantage that a magenta dye is changed to blue color or to red color.
Thus, a method for preventing color change or fading which has sufficiently great light-resistance and is resists color change due to heat or humidity is desired.